Added Steam Cloud Save system to fix progress loss issues after updates

[p]We have now added the Steam Cloud Save system, allowing you to play on different devices while retaining your progress.[/p][p]Due to previously collected feedback from players about progress loss issues caused by updates, all levels are now accessible. Levels are now categorized as either completed or not completed. To obtain collectible images, you only need to complete the final level of each map.[/p]